Full Factorial Experimental Design Research Articles

Influence of Process Parameters on the Tribological Behavior of PEO Coatings on CP-Titanium 4+ Alloys for Biomedical Applications

Wear resistant ceramic coatings were generated on novel commercially pure titanium grade 4+ alloys by the plasma electrolytic oxidation technique (PEO) in an aluminate and zirconia containing electrolyte. The coatings were obtained adopting a full regular two-level factorial design of experiments (DoE) varying the PEO process parameters current density, repetition rate and duty cycle. The generated coatings were characterized with respect to its wear resistance and mechanical properties by reciprocal ball-on-flat tests and nanoindentation measurements. Thickness, morphology and phase formation of the PEO coatings was analyzed by scanning electron microscopy (SEM/EDS) and X-ray diffraction. XRD results indicate the formation of crystalline aluminium titanate (TiAlO) as well as t-ZrO and alumina leading to an increase in hardness and wear resistance of the PEO coatings. Evaluation of the DoE’s parameter interaction shows that the main effects for generating wear resistant coatings are current density and repetition rate. In particular, the formation of mechanically stable and adhesive corundum and zirconia containing coatings with increasing current density and frequency turned out to be responsible for the improvement of the tribological properties. Overall, the PEO processing significantly improves the wear resistance of the CP titanium base alloy.

Relationship between the amino acid release kinetics of feed proteins and nitrogen balance in finishing pigs

In current nutrition requirements of swine, although the protein diets are formulated based on the ileal digestibility of protein and amino acid (AA), there is a difference in nitrogen utilisation among various protein diets, which might be related to the AA release kinetics. To evaluate the relationship between AA release kinetics of feed proteins and nitrogen balance in finishing pigs, pigs were fed diets based on casein (CAS) or corn gluten meal (CGM) at normal or low-protein concentrations, and the AA release patterns were assessed. A 2 × 2 full factorial experimental design was used. 24 pigs (Duroc × Landrace × Yorkshire) with an initial weight of 67.0 ± 1.8 kg were randomly assigned to consume a normal-protein casein-based diet (N.CAS, 10% CP), normal-protein corn gluten meal-based diet (N.CGM, 10% CP), low-protein casein-based diet (L.CAS, 8.5% CP), or low-protein corn gluten meal-based diet (L.CGM, 8.5% CP) for 14 days (n = 6 per group; pigs housed and fed separately). The low-protein diets were associated with a more rapid release of AAs in the early stages of gastric digestion than the normal-protein diets. The N.CAS and L.CAS diets were associated with a peak AA release at approximately 4 h during trypsin digestion, whereas N.CGM and L.CGM were at approximately 16 h. The N.CAS diet was associated with the least dispersed release curves and lowest synchronisation indexes, implying that it was associated with the best AA release synchronism, whereas the L.CGM diet was on the contrary. The nitrogen intake (NI), faecal nitrogen, urine nitrogen (UN), total nitrogen, net protein utilisation and apparent biological value (ABV) of protein of pigs fed the L.CAS or L.CGM diets were lower than those fed the N.CAS or N.CGM diets (P < 0.05). Notably, there was a difference in NI (P < 0.05) and trends with respect to UN and ABV (0.05 < P < 0.1), but no differences in retained nitrogen or apparent nitrogen digestibility between pigs fed the N.CAS or L.CAS diets and those fed the N.CGM or L.CGM diets. Pigs fed the N.CAS or N.CGM diets had higher serum concentrations of UN than pigs fed the L.CAS or L.CGM diets (P < 0.05), but there were no differences in serum total protein, albumin, triglyceride, glucose, alanine transaminase, or aspartate aminotransferase between the groups. In addition, there was an interaction between protein level and protein source on serum globulin (P < 0.05). Therefore, the diet with a better AA release synchronism can improve protein utilisation efficiency in finishing pigs and to reduce environmental pollution.

Optimization of a new multi-reagent procedure for quantitative mussel digestion in microplastic analysis

Over the last few years, different digestion protocols have been proposed to extract microplastics from mussels, an important product from aquaculture and a relevant economic resource, always scrutinized as a potential pollutant concentrator. In this study, a full factorial experimental design technique has been employed to achieve efficiency in removing biological materials while maximizing the recoveries of five common microplastics (polyethylene, polystyrene, polyethylene terephthalate, polypropylene and polyamide). A robust setpoint was calculated, 2.5% potassium hydroxide at 60 °C for 3 h with 5% hydrogen peroxide and 2.7% of methanol, permitting the quantitative digestion of mussel tissues and recovery of microplastics. These experimental conditions were successfully used to digest whole mussels bought from a local market, which possess high levels of microplastic contamination (41 items/g dry weight). The results highlight the importance of optimizing protocols to develop robust, easy to use and cheap quantitative approaches for analysing microplastic accumulation in edible organisms.

Prediction of bond strength in the fused shirt composites

Purpose Bond strength is an indicator of the quality of the fusing process. The study's primary purpose is to predict the bond strength using easily measurable variables. This study focuses on shirting fabrics fused with woven interlinings and changes in bond strength before and after washing. Design/methodology/approach This study attempts to model and predict bond strength of fused shirt composites using an initial screening design followed by full factorial design of experiments. After screening out, those found significantly affecting the bond strength are fabric fiber content, interlining areal weight and fusing temperature. This study proposes the regression models explaining the effect of the three variables on bond strength before and after washing the fused composites. Findings This study found that heavy interlinings (250 g/sq.m) require higher fusing temperatures than the lighter interlining (225 g/sq.m). After washing, the bond strength of samples fused at high temperatures reduced in some instances. Maintaining a high temperature without considering interlining weight can lower the bond strength after washing the fused composites. Originality/value A combination of screening and full factorial DOE is used to analyze and predict bond strength of composites comprising medium-weight shirting fabrics and heavier weight interlinings used in shirts.

Optimal Designed Experiments for Reliable Model Calibration of a fixed-speed Scroll Compressor with R410A and R32

Mainly to provide heat, the building sector accounts for about 18 % of overall global CO2 emissions. By exchanging conventional technologies in the near future, heat pumps are a key technology to systematically decarbonise the heat supply chain. The efficiency of a heat pump strongly depends on its compressor’s efficiency. Thus, the compressor is the subject of current research. The compressor performance depends on the fluid with its inlet and outlet conditions, an appropriate oil, and the mechanic compression principle. Based on that, the performance is expressed by the isentropic and volumetric efficiency. To describe a compressor in detail and fluid independent is challenging. Therefore, many theoretical studies have been conducted, while in comparison experimental studies are rare. To overcome this imbalance, this study focuses a detailed experimental investigation of a 4 kW Copeland scroll compressor with R410A and R32 on a fully automated compressor test stand. Within this paper, we present a method for in-depth uncertainty analysis, which ensures the usability and comparability of our experimental results to other experiments. We store our results in optimal calibrated simulation models based on optimal experimental design. This allows us to reduce experimental effort up to 70 % compared to full factorial experimental designs. To prove the method in a compressor and two fluids, we apply it to a fixed-speed scroll compressor with R410A and R32. The test stand is able to conduct all experiments automatically and part load behaviour of both refrigerants can be summarized in a model according to recent Literature with an overall uncertainty below 8 % for R410A. For R32, the method fails. Utilizing this method, we aim at open-source experiments in order to accelerate the solution of complex research questions.

The Need of Statistical Approach for Optimising Mixture Design of Controlled Low-Strength Materials

The statistical phase method was introduced to achieve optimal mixing controlled low-strength material (CLSM) proportions, utilising statistical studies. There is no well-known explicit formulation for predicting hardened properties (in terms of unconfined compressive strength (UCS)) of CLSM. The proposed approach to optimising CLSM mix design is demonstrated in the most common case where experimental mixing was considered in compliance with the full factorial experimental design involving three variables with two levels (2³) and the Box-Wilson central composite design (CCD) method. Twenty CLSMs with six replicates (one hundred and twenty specimens) were considered in changing the levels of the main factors that affect CLSM compression strength, the water/cementitious ratio (2.53-2.73) and the wastepaper ash (WSA) percentage (50-100%) and cementitious materials content (160-200 kg/m³). The experimental results were used to analyse variance and design a UCS polynomial regression equation for design factors considered in this research. In order to emphasise how to optimise CLSM mixtures with different options, a statistical model was developed.

Organometallic modified montmorillonite application in the wastewater purification: Pollutant photodegradation and antibacterial efficiencies

The ability of peptides to form stable complexes with metal ions offers a remarkable starting point for elaborating catalysts and antibacterial agents.This paper reports the synthesis and characterization of a new inexpensive organometallic-montmorillonite as highly active catalyst and antibacterial agent. An Fe(II)-Glycylglycylglycine (Fe-3Gly) complex was covalently anchored to montmorillonite K10 (K10) previously grafted with 3-aminopropyl-trietoxisilane (APTES). Multiple techniques were used to investigate the different steps of functionalization, to name FTIR, TGA, XRD, N2 adsorption–desorption technique, RD/UV–Vis, and SEM-EDS. The catalytic activity of the prepared catalyst was determined in terms of decolorization efficiency percentages of Congo Red dye (CR) in an aqueous solution using three types of Advanced Oxidation Processes (AOPs) that are the heterogeneous Fenton, the photocatalysis and photo-Fenton processes. A full factorial design of experiment was established in the photo-Fenton process in order to i) identify the most influential parameters and their interactions, and ii) determine the experimental conditions most favorable to the degradation. Thus, five factors were considered: catalyst weight (X1), H2O2 volume (X2), pH (X3), CR concentration (X4) and time (X5). From the statistical analysis, the correlation coefficient for the model was R2 = 0.90 and the most effective factor in the photo-Fenton degradation efficiency was the pH. The experimental values fitted with the predicted ones, thereby indicating the appropriateness of the established model. Furthermore, the prepared material showed good antibacterial activities.

Development, characterization and preclinical evaluation of nanosized liposomes of itraconazole for topical application: 32 full factorial design to estimate the relationship between formulation components

The objective of the study was to statistically develop a novel formulation of itraconazole (ITZ) loaded nanosized liposomes (NLPs) for effective topical delivery against superficial fungal infections. Target formulation was prepared by thin-film hydration, and was optimized by employing a two-step design of experiments (DoE) approach, which comprised a fractional factorial design for screening of ‘vital few’ factors, and response surface mapping optimized using a fractional factorial and 32 full factorial design of experiments. Overlay of response maps for percent drug entrapment (PDE), vesicle size, ITZ skin retention and permeation performed to obtain the optimized ITZ loaded NLPs (OPT-NLPs) suspension. The liposome suspension was gelled to improve topical applicability. OPT-NLPs formulation was able to show high PDE (78.69 ± 3.17%), and average vesicle size of 358.2 ± 9.45 nm and mean zeta potential of 20.66 ± 0.74 mV were observed. Additionally, noticeably higher ITZ skin retention (44.39 ± 1.32 μg/cm2) and cumulative 6-h drug permeation (14.81 ± 0.48 μg/cm2) were observed in excised rat skin in comparison to conventional cream and oily solution of ITZ. Also, standardized Tinea pedis animal model was used to evaluate in vivo antifungal efficacy observed in terms of physical manifestations, fungal-burden score and histopathological profiles. Rapid alleviation of infection in animals treated with optimized hydrogel was observed in comparison to those treated with commercial topical and oral antifungal therapies. Our study suggests that the developed formulation may be a promising and rapid alternative to conventional antifungal therapies against dermatophytosis.

Effect of the preparation techniques of photopolymerizable ceramic slurry and printing parameters on the accuracy of 3D printed lattice structures

Digital Light Processing (DLP) technology demonstrates the potential for manufacturing parts with complex structures for various engineering applications. The purpose of this study is to evaluate Al2O3 ceramic slurry preparation techniques, establish optimal processing window and assess the manufacturability and dimensional accuracy of lattice structures with CAD strut diameters of up to 500 μm. Two preparation techniques of the ceramic slurry were investigated. The slurry with the pre-treated powder showed appropriate rheological and photopolymerization behaviour. Full factorial Design of Experiments (DOE) was conducted to generate an experimental plan and assess the influence of the printing parameters on the dimensional accuracy. Analysis of Variance (ANOVA) revealed the exposure time, the exposure power, and the interaction effect of both had a significant influence on the dimensional accuracy of lattice strut diameters. The excess cure width was found to be dependent on the feature size, the energy dose and the layer thickness.

Contribution to the selection of cutting fluid type and its application technique for grinding of bearing steel

The elevated heat generation in grinding can develop high temperatures at the contact zone, which can adversely affect the surface integrity of the workpiece, especially when grinding hardened steels with conventional abrasives. Thus, the correct selection of cooling-lubrication condition is essential to avoid or attenuate any possible negative effect to workpiece surface integrity. However, the literature lacks work comparing different cutting fluid application technique (e.g. flood and minimum quantity lubrication – MQL) using the same fluid on both techniques. In this context, this work aims to contribute to the selection of cutting fluid type and its application technique for the grinding of bearing steel. Experimental trials were conducted comparing the use of semisynthetic and synthetic cutting fluids, both applied via conventional (flood) and MQL techniques. Different cutting conditions were also tested. A 24 full factorial design of experiment (DOE) was carried out with the following factors: fluid application technique, type of fluid, workspeed, and radial depth of cut. An analysis of main effects and interactions was performed for surface finish (Ra parameter) results, including a prediction model based on the analysis of variance (ANOVA). The morphology of ground surface and microhardness below machined surface were also analyzed. The results showed that the ground surface finish was strongly dependent on the cutting fluid type and its application technique combination: superior finishing was observed with the combination of semisynthetic fluid delivered via flood technique and with synthetic fluid delivered via MQL technique. From the surface morphology analysis, it was observed that the inferior lubrication capacity of synthetic fluid applied via flood condition deteriorated the surface finish and morphology. The surfaces ground with semisynthetic fluid provided, in general, lower values of Ra and lower microhardness variation. The prediction model for Ra showed a maximum error of 14% in comparison to the measured values.

Co-solidification of bauxite residue and coal ash into indurated monolith via ambient geopolymerisation for in situ environmental application

Bauxite residues generated from alumina refineries worldwide have accumulated to more than 4 billion tons, at an annual increment of ~ 0.15 billion tons. It is imperative and urgent for the alumina sector to develop field-operable disposal solutions for rapid and cost-effective stabilisation of alkaline bauxite residues (BR) in the storage facility to minimise/prevent potential environmental risks. Taking advantage of the availability of coal ash (CA) on site, we studied a feasible way to synthesise geopolymer from active (amorphous) aluminosilicate components of BR and CA via the alkaline hydrolysis under ambient conditions. The new geopolymeric binder effectively solidifies BR-CA mixtures into indurated monoliths whose unconstrained compressive strength (UCS) can reach as high as ~ 20 MPa after 8 weeks. The Full Factorial Experimental Design was used to study relative influences of BR:CA ratio, modulus of activating solution, and H2O/Na2O ratio on UCS. Micro-spectroscopic structural analyses using electron-dispersive X-ray spectroscopy and X-ray Photoelectron Spectroscopy suggested a co-occurrence of cement-like calcium aluminosilicate hydrate (C-A-S-H) and Na-rich aluminosilicate 3D-extended network (geopolymer) within the binder phase. The advantage of this ambient geopolymerisation, without resorting to elevated temperature curing, renders a feasible way of valorising BR and CA for environmental management of alkaline wastes at alumina refineries.

The effects of infill patterns and infill percentages on energy consumption in fused filament fabrication using CFR-PEEK

PurposeThis study aims to identify the effects of infill patterns and infill percentages on the energy consumption (EC) of fused filament fabrication (FFF). With increasing attention on carbon-fiber-reinforced–poly-ether-ether-ketone (CFR-PEEK) for practical applications in FFF, infill pattern and infill percentage for FFF can be properly controlled to achieve better energy performance of CFR-PEEK outputs. However, the effects of infill parameters on EC for FFF using CFR-PEEK have not been clearly addressed yet.Design/methodology/approachUsing a full factorial experimental design, six types of infill patterns (rectilinear, grid, triangular, wiggle, fast honeycomb and full honeycomb) and four different infill percentages (25%, 50%, 75% and 100%) were considered for a design of experiments with three replicates. Then, analysis of variance, Tukey test and regression analysis were performed to investigate both the effects of infill pattern and infill percentage on energy performance during FFF.FindingsEC is characterized to be high for the wiggle and triangular patterns and low for the rectilinear pattern during both the printing stage and the entire process. The wiggle pattern results in the greatest increase in EC, whereas the rectilinear pattern leads to the least increase in EC. Although EC during the FFF process increases as the infill percentage increases, the average power demand during the printing stage decreases.Originality/valueBoth the main and interaction effects of infill pattern and infill percentage are investigated to estimate EC and power during the different process stages of FFF.

Should Facebook advertisements promoting a physical activity smartphone app be image or video-based, and should they promote benefits of being active or the app attributes?

Social media provides a convenient platform for health campaigns. However, practitioners designing such campaigns are faced with a number of decisions regarding advertising formats and appeals. This study set out to compare the effectiveness of two advertising formats (image vs. video) and two advertising appeals (benefits of being active vs. app attributes and features) for promoting a physical-activity smartphone app. The advertising experiment was conducted on Facebook and employed a 2 × 2 full-factorial experimental design, examining two advertising formats: image versus video and two advertising appeals: benefit versus attribute. Outcome measures were advertisement cost (number of viewers reached according to the amount spent) and consumer engagement (rates of advertisement click-through and app downloads). Chi-Square analysis revealed that advertisement cost was found to differ according to the type of advertising format used, with image advertisements achieving a greater audience reach than video advertisements (χ 2(1) = 905.292, p < .001). Consumer engagement also differed according to advertising format and appeal: images achieved high rates of advertisement click-through (2.7% vs. 1.9%; χ 2(1) = 196.9, p < .001) and app downloads (0.6% vs. 0.5%; χ 2(1) = 4.0, p = .044) compared with videos. Furthermore, benefit appeal advertisements were more effective than attribute appeals, yielding a greater rate of advertisement click-through (2.8% vs. 1.8%; χ 2(1) = 282.2, p < .001) and app downloads (0.7% vs. 0.4%; χ 2(1) =106.0, p < .001). Overall, image advertisements were seen to be the most cost-effective and engaging. Advertisements employing a benefit appeal achieved greater consumer engagement than and attribute appeal advertisements.

Interactions between developmental and adult acclimation have distinct consequences for heat tolerance and heat stress recovery.

Developmental and adult thermal acclimation can have distinct, even opposite, effects on adult heat resistance in ectotherms. Yet, their relative contribution to heat-hardiness of ectotherms remains unclear despite the broad ecological implications thereof. Furthermore, the deterministic relationship between heat knockdown and recovery from heat stress is poorly understood but significant for establishing causal links between climate variability and population dynamics. Here, using Drosophila melanogaster in a full-factorial experimental design, we assessed the heat tolerance of flies in static stress assays, and document how developmental and adult acclimation interact with a distinct pattern to promote survival to heat stress in adults. We show that warmer adult acclimation is the initial factor enhancing survival to constant stressful high temperatures in flies, but also that the interaction between adult and developmental acclimation becomes gradually more important to ensure survival as the stress persists. This provides an important framework revealing the dynamic interplay between these two forms of acclimation that ultimately enhance thermal tolerance as a function of stress duration. Furthermore, by investigating recovery rates post-stress, we also show that the process of heat-hardening and recovery post-heat knockdown are likely to be based on set of (at least partially) divergent mechanisms. This could bear ecological significance as a trade-off may exist between increasing thermal tolerance and maximizing recovery rates post-stress, constraining population responses when exposed to variable and stressful climatic conditions.

Modelling flexural performance of hollow pultruded FRP profiles

Hollow Pultruded Fibre-Reinforced Polymer (PFRP) profiles, as novel construction material, require further development of design tool to broaden the applications. This paper proposes a combined experimental and numerical methodology as a design tool to investigate the failure modes of these profiles under four-point bending. Two different profiles, each with 10 samples, were tested until failure and were used to validate the numerical model. A finite element model was built based on a fast-convergence incremental approach that suits flexural loading and reduces the computational cost. The validated model was used to study the failure sequence thoroughly and perform an extensive parametric study on the design parameters. Each geometric parameter was studied individually first to determine the relevant levels for each parameter in the full factorial study. A full factorial design of experiment was used to capture the critical parametric interactions with over 81 numerical models. The design rules and recommendation were established for the optimal flexural behaviour of hollow box PFRP profiles to withstand local buckling of the top flange.

Optimization of a Patient-Specific External Fixation Device for Lower Limb Injuries.

The use of external fixation devices is considered a valuable approach for the treatment of bone fractures, providing proper alignment to fractured fragments and maintaining fracture stability during the healing process. The need for external fixation devices has increased due to an aging population and increased trauma incidents. The design and fabrication of external fixations are major challenges since the shape and size of the defect vary, as well as the geometry of the human limb. This requires fully personalized external fixators to improve its fit and functionality. This paper presents a methodology to design personalized lightweight external fixator devices for additive manufacturing. This methodology comprises data acquisition, Computer tomography (CT) imaging analysis and processing, Computer Aided Design (CAD) modelling and two methods (imposed predefined patterns and topology optimization) to reduce the weight of the device. Finite element analysis with full factorial design of experiments were used to determine the optimal combination of designs (topology optimization and predefined patterns), materials (polylactic acid, acrylonitrile butadiene styrene, and polyamide) and thickness (3, 4, 5 and 6 mm) to maximize the strength and stiffness of the fixator, while minimizing its weight. The optimal parameters were found to correspond to an external fixator device optimized by topology optimization, made in polylactic acid with 4 mm thickness.

A new ductile iron for mechanically and thermally strained rolls Part 2: material development varying Ni, Mo, Cr content using DoE

ABSTRACT For manufacturing of steel wires, tubes and profiles in hot rolling mills, the toughest conditions occur in the front rolling stands where the mechanical load comes along with a constant change of hot rolling stock and cooling liquid. Conventional roll materials as pearlitic or acicular cast irons are not able to overcome these intense conditions because of their lack of ductility. A fine selection of alloying elements leads to a new material with a microstructure uniting bainite, austenite and martensite inducing high hardness and strength, without lacking elongation. For this purpose, a full-factorial design of experiments was created consisting of three alloying elements in two concentrations each. The alloys were cast, heat-treated and underwent extensive investigations on mechanical properties and microstructure. The results were analysed and implemented in mathematical models whose combination and optimisation led to the identification of the ideal alloy meeting the required strength, hardness and elongation.

Biocatalyzed Synthesis of Flavor Esters and Polyesters: A Design of Experiments (DoE) Approach.

In the present work, different hydrolases were adsorbed onto polypropylene beads to investigate their activity both in short-esters and polyesters synthesis. The software MODDE® Pro 13 (Sartorius) was used to develop a full-factorial design of experiments (DoE) to analyse the thermostability and selectivity of the immobilized enzyme towards alcohols and acids with different chain lengths in short-esters synthesis reactions. The temperature optima of Candida antarctica lipase B (CaLB), Humicola insolens cutinase (HiC), and Thermobifida cellulosilytica cutinase 1 (Thc_Cut1) were 85 °C, 70 °C, and 50 °C. CaLB and HiC preferred long-chain alcohols and acids as substrate in contrast to Thc_Cut1, which was more active on short-chain monomers. Polymerization of different esters as building blocks was carried out to confirm the applicability of the obtained model on larger macromolecules. The selectivity of both CaLB and HiC was investigated and best results were obtained for dimethyl sebacate (DMSe), leading to polyesters with a Mw of 18 kDa and 6 kDa. For the polymerization of dimethyl adipate (DMA) with BDO and ODO, higher molecular masses were obtained when using CaLB onto polypropylene beads (CaLB_PP) as compared with CaLB immobilized on macroporous acrylic resin beads (i.e., Novozym 435). Namely, for BDO the Mn were 7500 and 4300 Da and for ODO 8100 and 5000 Da for CaLB_PP and for the commercial enzymes, respectively. Thc_Cut1 led to polymers with lower molecular masses, with Mn < 1 kDa. This enzyme showed a temperature optimum of 50 °C with 63% of DMA and BDO when compared to 54% and 27%, at 70 °C and at 85 °C, respectively.

Optimization of TiO2 immobilized – Reduce graphene oxide photocatalyst toward organic compounds in aqueous medium

In this work, a one-pot hydrothermal route was synergistically applied for TiO2 immobilized reduced graphene oxide (TiO2/rGO) facilitation. The material was characterized by modern analysis methods and studied the photocatalytic performance with methylene blue (MB) in the water. The characteristic results expressed that TiO2 in truncated octahedral bipyramidal structure with 4–25 nm was disseminated onto the rGO base. Simultaneous effects of the reaction temperature, pH, adsorption time, photocatalytic time, MB concentration, and catalyst dosage on the MB photodegradation of TiO2/rGO were also conducted by full factorial experimental design according to Placket–Burman and Box–Behnken designs. At room temperature, after 2h–adsorption and photodegradation with MB concentration of 23 mg/L in pH of 10 solution and 20 mg catalyst, nearly 100% of MB was productively decomposed out of the medium with a relatively high reaction rate constant. The photocatalytic performance showed an excellent impact toward other types of organic contaminants with the above condition, indeed affirming an extensive use in wastewater treatment with organic pollutants.

Dissimilar friction stir lap welding of AA2198 and AA7075 sheets: forces, microstructure and mechanical properties

This paper investigates the dissimilar friction stir lap welding of AA2198 and AA7075 sheets. The influence of processing parameters, namely welding speed and tool rotational speed on joint features, microstructure, and mechanical properties were studied by implementing a full factorial design of experiments. Axial and transversal forces were continuously measured during the welding process using a sensed fixture aiming at the correlation of processing parameters, forces, and quality of the achieved joints. Obtained outcomes showed hook formation for all the combination of parameters and the existence of a very narrow processing window in which it is possible to avoid the formation of internal defects, such as grooves and tunnels. The influence of the weld bead morphology on the lap shear strength was elucidated proving that the strength is ruled by the hook morphology. The microstructure of the joints was studied and discussed considering also the microhardness distribution.Graphical abstract